In-line connector seals for use in circulating systems usually require two cooperating halves. Most designs are such that each half has a cylindrical axis parallel to flow, and engagement of the halves is accomplished by urging the halves together along the cylindrical axis. Generally, the halves have a “gendered” design, such that two differently-designed halves are required to complete a single seal. “Genderless” connector systems, which generally require only a single piece design, function by the interlocking of two substantially identical pieces in order to form the seal. The convenient, symmetric design of genderless connectors simplifies manufacture of sealing system components in that only one piece need be designed and fabricated. The piece shape is such that it is structurally self-complementary: two substantially identical pieces, each having essentially the same design, can be interlocked to complete a seal. The word “substantially” as used herein is intended to include within the ambit of the meaning of the term “genderless connector” connectors in which exist slight differences in design, between the pieces, which are not material to the act of forming the seal.
However, the features which make genderless designs simple to use, such as simplicity of design and manufacture, as well as minimal number of components, can limit them with respect to certain types of seal locations and environments. For example, “collar-type” genderless connector designs generally employ two collar elements, each of which seats a phlange-type “face element.” The “face elements” are immobilized in face-to-face contact by urging the collar elements together along the axis of expected flow (the cylindrical axis) such that the collar elements come into contact and are immobilized, such as, for example, by a circumferential clamp. Such a system can easily be employed if a collar element can be inserted in line (such as, for example, by opening and reclosing a circulating system line) and brought into contact with the back of a face element component. Genderless connectors involving collar elements attached to circulatory tubing can be used where a free end is available such that the collar element can be installed either by threading it onto the circulator tubing to the rear of the face element, or detaching the face element from its connective tubing, inserting the collar element over the detached tubing end, and reattaching the face element.
However, in many applications, a seal is required at a position which is inaccessible to standard collar elements. For example, an integral or otherwise irremovable port, such as port vessel bearing a welded fitting, cannot be easily modified to accept an inline addition. The face component of the port may be attached to the vessel in a manner which prevents breaking the line and sliding a collar into contact with the back of the face component.
In such cases, if a collar element is to be used, it must be assembled about the tubing to form a closed element, preferably with only minimal loss of structural integrity relative to one-piece molded collar element components. However, the requirement for multiple pieces can eliminate the manufacturing and use advantages associated with genderless collar element designs. Furthermore, a collar formed from two or more separate pieces can be expected to lack the structural integrity of a one piece collar. Lack of structural integrity has contributed to the failures of other multipart systems of similar nature. For example, the process of completing or reopening the seal can often force the components of a two-part seal fitting apart due to the resultant forces upon the components as the two-piece seal fitting is linked up with a one-piece seal fitting.
Furthermore, the need for two different pieces in order to assemble one seal fitting complicates fabrication, purchasing, storage, and implementation of the sealing assembly.
As an example of the types of fittings encountered in the pharmaceutical, dairy, food and beverage industries, the use of the sanitary coupling system for fluid connections defined in ISO 2852 and the ASME-BPE Standards of 2009 is widespread. Such couplings can be stainless steel welded couplings as well as plastic disposable fittings. It is necessary that the plastic disposable fittings fit the stainless steel sanitary couplings that may be welded into place on piping or tanks. Two sanitary couplings involved in a connection are often held in contact by an external sanitary hinged screw clamp.
Because of the need for a front mountable seal fitting, there have been attempts to employ a multipart system which externally secures two sealing members. However, many such systems must be secured with additional accessories, such as clamps, or they include connecting mechanisms which require fragile, flexible tabs, which, in the case of one-piece molded components, generally break off easily or easily undergo irreversible deformation. Thus, with regard to two-piece seal fittings, replacement of the components is often required upon seal opening and reforming.
Designs containing “living hinges” comprise flexible elements which connect the components, such as a flexible bridge of polymeric material. Such connections can be prone to stretching or breaking. For example, the act of forcing a component closed about a sealing interface can leverage the flexible connecting element, stressing or inelastically deforming it. Both effects can reduce the ability of the element to draw sealing faces together to form a tight seal, particularly with repeat use. Furthermore, the inclusion of a flexible element can greatly complicate the one-piece manufacture of the element. For example, with respect to common molding procedures, such as one-piece molding, the mold would generally include the flexible element, which would most conveniently be of the same material as the components connected by it, thus limiting the range of materials which can be employed in the fabrication. Another disadvantage of living hinges is that seal fittings comprising them can only open on one side, placing limits on its working orientation and limiting the manner in which the seal can be opened and reclosed. A general characteristic of the living hinge-containing system is that articulation essentially takes place about an axis which is essentially the center of the hinge. While forces encountered in completing the sealing assembly generally do not cause a complete separation of the subelements, the connector can be weakened from simple repetitive articulation, and deformed or stretched by prolonged tight closure about a face element. Tension upon full closure of the seal fitting halves about the face element can stretch or deform the living hinge.
The foregoing notwithstanding, there is a need for a seal fitting which can be 1) front-mounted on circulating systems without breaking into circulatory line tubing or other conduits, and 2) opened and reclosed accessibly, without compromising the sealing integrity of the sealing assembly or the mechanical integrity of a one-piece system.
Furthermore, it is desirable that a seal fitting incorporate characteristics of a living hinge, such as the capacity to similarly articulate to an open configuration, optionally, with the articulation centered about a single locus, as with a hinge. However, it is desirable that the accessibility of the seal via the seal fitting be increased relative to that of a living hinge, such that the seal fitting can be opened from more than one locus for increased ease of application and removal of the seal fitting. Further desired is a seal fitting, which, like a living hinge, will not readily separate into subcomponents upon articulation, yet, unlike a living hinge, can be initially installed by combining two separate subcomponents. Preferred is a seal fitting which, when exercised into an open articulation resists separation into two subcomponents by the application of independent linear forces, for example, diametrically opposite forces, such as would be experienced by the seal fitting upon articulation and removal. Also desired is a seal fitting having the ability to hold sealing faces together firmly, yet allowing easy access to the sealing faces such that the seal can be opened and reformed, if necessary, with no loss in sealing efficiency. Furthermore, a seal fitting design which met the above criteria, but also comprising substantially identical subsections, would greatly simplify production in that only a single type of piece would need to be purchased and stored to fabricate the collar.